#include <functional>
#include <iostream>


using task_t = std::function<void(std::string)>;

void task(std::string name){
    std::cout << "task doing..." << " task done." << std::endl;
}

// struct task_t2{
//     void operator()(std::string name){
//         std::cout << "task 2 doing..." << " task 2 done." << std::endl;
//     }
// };
